Answer:
At the critical angle the angle of refraction (outside the medium) is 90°
Ni sin θ = Na sin 90° = 1 assuming outside medium is air
sin θ = 1 / Ni where Ni is the refractive of the medium involved
A cross-country runner runs 4 km in 15 minutes. What can you calculate using this information?
One can calculate speed from the given data. The speed is 4.44m/s.
What is speed?The speed is the ratio of distance and the time taken to cover that distance.
Given is the distance d =4km =4000m and the time taken t 15 min =15 x60 =900 s
Then the speed will be
s = d/t
s = 4000/900
s= 4.44 m/s
Thus, the speed is calculated as 4.44m/s.
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15 PNTS
Select the correct answer. Which of the following is not produced in fission reactions?
A. greenhouse gases
B. heat
C. isotopes
D. neutrons
Answer:
A. Greenhouse gases
Explanation:
Because nuclear fission involves the modification of atoms.
Answer:
Greenhouse gases, because in nuclear fission, we are talking about modifying strictly atoms to get a reaction, therefore it would not make sense for greenhouse gases to be a reaction.
where are most of the comets in our solar system found?
Answer:
some far beyond the edge of the solar system called the Oort Cloud, and some beyond Neptune in a region called the Kuiper Belt.
Explanation:
Hopefully this helps
Whats the difference between a lunar and solar eclipse?.
Answer: there is no shadow on the Moon with the solar eclipse.
Explanation: When the Moon passes between the Earth and the Sun, it casts a moving shadow on the Earth's surface, known as a solar eclipse. When the Earth passes between the Sun and the Moon, a lunar eclipse occurs, creating a shadow on the Moon.
Which pair of atoms will form a covalent bond? a. One atom of Fluorine and two atoms of Oxygen
b. two atoms of lithium and one atom of chlorine
c. one atom of magnesium and two atoms of sulfur
d. three atoms of potassium and one atom of phosphorus
Answer:
a.one atom of fluorine and two atoms of oxygen
Explanation:
hope it help
Question 21 of 25
If an electromagnetic wave has a frequency of 8 x 1014 Hz, what is its
wavelength? Use a = . The speed of light is 3 x 108 m/s.
?
3 x .
V
f
O A. 2.7 x 10-6 m
O B. 3.8 x 1021 m
O C. 3.8 x 10-7m
O D. 2.7 x 106 m
SUBMIT
A dolphin leaps out of the water
at 6.25 m/s at a 45.0° angle.
How far away does it land?
(Unit = m)
x max = (vi² sin 2α) / g
x max = (6.25² sin 90)/10
x max = 39.0625/10 = 3.91 m
A car moving with a velocity of 30 ms-1 is stopped by the application of brakes which imparts a radiation of 6 ms-2 to the car.
1. how long does it take for the car to come to stop
2. how far does the car travel during the time the brakes are applied
somebody please help me solve this and do explain..
[tex]\huge{\color{red}{\fbox{\textsf{\textbf{Answer}}}}} [/tex]
1) 5 seconds
2) 75 meters
Explanation:
Refer to the attachment
How do astronauts counteract the effects of microgravity on their bones while they are in space?.
Answer:
they use a spaceship plus oxygen space has a gravitational force
A force applied to a spring compresses the spring 11 cm, storing a certain amount of elastic potential energy. Then a larger force is applied to compress the spring a total of 66 cm. How does the elastic potential energy stored in the spring after it is compressed 66 cm compare to the elastic potential energy stored in the spring after it was compressed 11 cm
Let k be the spring constant.
• When the spring is compressed by 11 cm = 0.11 m, it stores
1/2 k (0.11 m)²
of potential energy.
• When it's compressed by 66 cm = 0.66 m, it stores
1/2 k (0.66 m)²
of potential energy.
Then the ratio of these potential energies is
(1/2 k (0.66 m)²) / (1/2 k (0.11 m)²) = 36
which is to say, the spring stores 36 times more energy when it's compressed by 66 cm compared to 11 cm.
What is the magnitude of the force needed to keep a 60. -newton rubber block moving across level, dry asphalt in a straight line at a constant speed of 2. 0 meters per second?.
Answer:
A force of μk⋅60N is needed to keep a 60-newton rubber block moving across level, dry asphalt in a straight line at a constant speed.
Explanation:
Good evening! Can someone please answer this, ill give you brainliest and your earning 50 points. Would be very appreciated.
Answer:
Drinking water
Direct as we are achieving water directly by ourselvesOur foods
Indirect as foods contain water we are getting water indirectly from themWashing clothes
Direct as direct contact of water is hereA set of water waves travels at 10.0 m/s , and 5.0 waves pass you in 4.0 s. What is the wavelength of the waves?
Answer:
8 meters
Explanation:
Frequency of waves = 5 waves / 4 s = 1.25 Hz
speed = frequency * wavelength
speed/ frequency = wavelength
10 / 1.25 = 8 m
Question 7.
When can a mouse have the same momentum as an elephant?
د ن ه ه
A. when the mouse has a large velocity and the elephant has a small velocity
when the mouse has a small velocity and the elephant has a large velocity
a mouse cannot have the same momentum as an elephant
D. when they both have the same velocity
A mouse have the same momentum as an elephant when the mouse has a large velocity and the elephant has a small velocity. The correct option is A.
What is momentum?The momentum is the product of the mass of the object and its velocity.
Mouse has mass very less than the elephant. In order to make their momentum same, the velocity of the mouse must be greater than the elephant.
Mm x Vm = Me x Ve
A mouse have the same momentum as an elephant when the mouse has a large velocity and the elephant has a small velocity.
Thus, the correct option is A.
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A tuning fork consists of two metal prongs that vibrate at a single fre- quency when struck lightly. What will happen if a vibrating tuning fork is placed near another tuning fork of the same frequency
Resonance would occur when a vibrating tuning fork is placed near another tuning fork of the same frequency.
What is resonance?Resonance can be defined as a phenomenon in which a physical object is forced to vibrate due to the vibration of a second object at the same natural frequency of the first object.
This ultimately implies that, resonance is an increase in the amplitude of oscillation that only occurs when the frequency of a periodically applied force is equal to the natural frequency of a physical object such as a tuning fork, on which it's acting.
In conclusion, we can infer and logically deduce that resonance would occur when a vibrating tuning fork is placed near another tuning fork of the same frequency.
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Work is being done when
Answer:
To express this concept mathematically, the work W is equal to the force f times the distanced, or W = fd. If the force is being exerted at an angle θ to the displacement, the work done is W = fd cos θ.
The SI unit of work is the joule (J). It is defined as the work done by a force of one newton through a distance of one meter.
Explanation:
Work is done when a force is applied to an object through a distance. This means that when a force is applied to an object through a distance, the object's total energy will be affected.
PLEASE HELP
Which of the following is a characteristic property of the alkaline earth
metals?
A. They are harder than alkali metals.
B. They are more reactive than alkali metals.
C. They all have 3 valence electrons.
D. They are all radioactive.
Answer:
It's D, they're all radioactive. This is due to the molecules that it is made up of
Answer:
the answer is A
Explanation:
I hope it helps you
A circular loop of wire is placed in a uniform magnetic field directed out of the page. Suddenly the magnetic field disappear . What is the direction of the induced current in the loop?
Hi there!
Counterclockwise.
If a loop of wire is placed in a magnetic field directed out of the page that disappears, that means that the magnetic flux out of the page through the loop has decreased.
The loop will try to oppose this change in the magnetic flux, so an induced current that produces an additional magnetic field out of the page will occur to make up for the decrease in the magnetic flux.
Using the magnetic right-hand rule, the current in the loop would need to be traveling in the counterclockwise direction in order for the produced magnetic field to be directed out of the page inside the loop.
A boat moves 3.0 km due north and then moves 1.0 km due south. The time for this trip is half an hour. What is the average velocity of the boat
The average velocity of the boat given the data from the question is 6.32 Km/h
What is velocity?Velocity is defined as the rate of change of displacement with time. Mathematically, it is expressed as
Velocity = displacement / time
How to determine the resultant displacementDisplacement 1 (d₁) = 3 KmDisplacement 2 (d₂) = 1 KmResultant displacement (D) =?
D² = d₁² + d₂²
D² = 3² + 1²
D² = 9 + 1
D² = 10
Take the square root of both sides
D = √10
D = 3.16 Km
How to determine the average velocityResultant displacement = 3.16 KmTime = 1/2 hour = 0.5 hourAverage velocity =?
Average velocity = resultant displacement / time
Average velocity = 3.16 / 0.5
Average velocity = 6.32 Km/h
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7
What was the dependant variable? * is it 1,2 or 3?
(1 Point)
1. Type and weight of the block
2. increase in energy transferred
3. Thermometer used
Answer:
Increase is energy transferred
Explanation:
Increase in energy or ∆E depends upon the mass or type of the blockIt also depends upon the surface area etc The thermometer used is useless in this case .Option B is correct
I need help with this! Which one?
Answer:
I believe that it is the 1st one
What happens when a sound wave passes by the particles of a medium?
Answer:
Propagation of Sound Waves:
Sound waves move (propagate) through a medium by means of particle-to-particle interaction. The source disturbs the immediately surrounding particles, causing them to vibrate about their fixed position at the same frequency as the source.
Question 8
If a cheetah can run at a speed of 100 km/h for the initial 500 m of its chase, h
much time would it take to catch its prey that is at a distance of 100 m?
O 1.5 s
O 2.3s
O 3.6s
O 4.8s
Answer:
3.6 s
Explanation:
100 km/hr =27.77 m/s
100/27.77=3.6 sec
A bicyclist heads east at 20 km/h. After she has traveled 20.8 kilometers, another cyclist sets out in the same direction going 28 km/h. About how long will it take the second cyclist to catch up to the first cyclist
Hence,the time it takes the second cyclist to catch up to the first cyclist will be 2.6 h.
What is velocity?The change of displacement with respect to time is defined as the velocity. Velocity is a vector quantity. it is a time-based component.
[tex]\rm D_{rel}= V_{rel}\times t_{rel} \\\\ \rm D_{rel}= (V_1-V_2)\times t_{rel} \\\\ T_{rel}=\frac{D_{rel}}{V_1-V_2} \\\\ T_{rel}=\frac{20.8}{28-20} \\\\ T_{rel}= 2.6 \ h[/tex]
The time it takes the second cyclist to catch up to the first cyclist will be 2.6 h.
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Two charged plates separated by 15 cm create a uniform electric field of 360 n/c. what is the potential difference between the plates?
When two charged plates are separated by a distance, the potential difference between the plates is 54 Volts.
What is uniform electric field?The electric field intensity which does not increase or decrease with time or remain constant is called the uniform electric field.
Given is the plates separated by distance d = 15 cm =0.15 m, electric field E= 360 N/C.
The relation between the electric field and voltage is
E=V/d
Substitute the values into the expression to get the potential difference V,
V = 360 x 0.15
V = 54 Volts
Thus, the potential difference between the plates is 54 Volts.
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Write the relation between mass and weight of a body
Answer:
[tex]\text{Weight} = \text{Mass} \times \text{Gravitational acceleration}[/tex]
Explanation:
1. What is the angle of inclination of the Earth’s axis?
2. Which hemisphere is tilted toward the Sun?
3. Which hemisphere is tilted away from the Sun?
4. Which hemisphere receives greater amount of sunlight?
5. Why do places that receive direct rays of the Sun have warmer temperature?
Answer:
What is the angle of inclination of the Earth’s axis?The earth's axis of rotation is tilted 66.5 degrees with respect to its orbital plane around the sun and its axis of rotation is inclined 23.5 degrees from the perpendicular, with respect to this plane. The tilt of the earth affects the angle between the sun beam and the normal over a surface.
Which hemisphere is tilted toward the Sun?Earth orbits at an angle, so half the year, the Northern Hemisphere is tilted toward the Sun — this is summer in the Northern Hemisphere, and winter in the Southern Hemisphere. The other half of the year, the Northern Hemisphere is tilted away from the Sun, creating winter in the north and summer in the south.
Which hemisphere is tilted away from the Sun?When the Earth's axis is tilted toward the sun for the Northern Hemisphere, the people in the Northern Hemisphere experience summer, while at the same time, the Southern Hemisphere is tilted away from the sun and the people there experience winter.
Which hemisphere receives greater amount of sunlight?The Northern Hemisphere receives the maximum intensity of the sun's rays, while the angle of sunlight decreases in the Southern Hemisphere.
Why do places that receive direct rays of the Sun have warmer temperature?When the sun's rays strike Earth's surface near the equator, the incoming solar radiation is more direct (nearly perpendicular or closer to a 90˚ angle). Therefore, the solar radiation is concentrated over a smaller surface area, causing warmer temperatures.
Here is your answer please mark as brainlest answer!!Answer:
xfxy naa
Explanation:
dhdhuciffbfjfufu
1 astronomical unit (A) is
149,597,871 kilometres
hope it helps...!!!
Throughout this lesson, you learned about the lives and contributions of key scientists in this area of physics. Create a timeline that ties them all together. The timeline does not need to be highly detailed, but it should do the following:
Include at least the four major scientists covered in this unit: Oersted, Ampère, Faraday, and Tesla.
Include key contributions of each scientist and provide a year, if possible, for those contributions.
Note any relationships among these and other scientists, especially if one developed something based on the work of another.
Arrange the scientists chronologically by their first key contribution, not by their birth date.
Oersted -Electromagnetic theory in 1820(July).
Ampere - Static needle -a component of galvanometer in 1820 (September).
Faraday - Electromagnetic induction in 1831.
Tesla - First Alternating current motor and transmission system in 1882.
What is magnetic field?The region of space where a charged object moves in the direction of magnetic force and induces current.
Thus, the scientist are arranged chronologically with their key inventions.
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A boy pushes a toy car along the floor at a steady speed. Are the forces on it balanced
or unbalanced?
Answer:
the forces are balanced :)
Explanation:
